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Blog Support for Growing Mathematicians

### Each Number is Significant!

April12

Every number is significant, even small ones that seem insignificant! For example, I was talking with a parent recently who told me that if they give a dose of medicine to an animal and it is incorrectly measured by 2% then it will kill the animal. I must admit that I was quite stunned by that small difference. When I was a Junior in High School (6th form for those English and New Zealand students) my math teacher told me of a hike he did with a group. For some reason he and a friend made a slightly small deviation from the others and, after a couple of hours, discovered that they were several hundred meters apart – on opposite sides of a large ravine! Yes, small numbers or amounts do matter. Anyway, this month’s Number of the Month is 45, sourced from bestmaths.net:

45 – Number of the Month (April 2017)

• 45 is a triangular number, and in particular the sum of all the decimal digits
• (0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45)
• The factors of 45 are 1, 3, 5, 9, 15 and 45
• 45 in Roman numerals is expressed as XLV
• 45 is 101101 in binary.
• 45 is the atomic number of Rhodium.
• There are 45 degrees in half of a right angle.
• +45 is the telephone dialing code for Denmark.
• World War Two ended in 1945.

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#### Post Support

10 x 9 x 8 + (7 + 6) x 5 x 4 x (3 + 2) x 1 = 2020

NCEA Level 2 Algebra Problem. Using the information given, the shaded area = 9, that is:
y(y-8) = 9 –> y.y – 8y – 9 =0
–> (y-9)(y+1) = 0, therefore y = 9 (can’t have a distance of – 1 for the other solution for y)
Using the top and bottom of the rectangle,
x = (y-8)(y+2) = (9-8)(9+2) = 11
but, the left side = (x-4) = 11-4 = 7, but rhs = y+? = 9+?, which is greater than the value of the opp. side??
[I think that the left had side was a mistake and should have read (x+4)?]